jonathan preston dissertatio preston dissertation.pdf · pdf file jonathan preston b.s....

Click here to load reader

Post on 22-Jul-2020

1 views

Category:

Documents

0 download

Embed Size (px)

TRANSCRIPT

  • ABSTRACT

    Some children with speech sound disorders (SSD) have difficulty with literacy-

    related skills. In particular, they often have trouble with phonological processing, which

    is a robust predictor of early literacy. This study investigates the phonological processing

    abilities of preschoolers with SSD and uses a regression model to evaluate the degree to

    which these abilities can be concurrently predicted by types of speech sound errors.

    Forty-three English-speaking preschoolers (ages four to five) with SSD of

    unknown origin participated in an assessment of phonological processing skills and

    speech sound production. Productions elicited on a 125-item picture naming task were

    phonetically transcribed, and errors were coded in two ways: (1) according to Percent

    Consonants Correct (PCC), which weights all consonant errors equally, and (2) according

    to a three-category system: typical sound changes, atypical sound changes, and

    distortions. Phonological awareness (PA) was assessed via rhyme matching, onset

    (initial consonant) matching, onset segmentation and matching, and blending.

    Phonological memory was assessed using a syllable repetition task. Children also rapidly

    named pictures of monosyllabic and disyllabic words.

    Results showed that performance on a PA composite score could be predicted, in

    part, by vocabulary and age (about 33%). Atypical sound changes were found to account

    for additional variance in PA (another 6%), but distortions and typical errors did not

    account for significant variance in PA. Thus, use of more atypical sound changes was

    associated with poorer performance on PA tasks. When the same consonant errors were

    classified using PCC, speech sound errors were not found to predict significant variance

    in PA. Atypical sound changes also significantly predicted variance in phonological

  • memory (about 31%) and rapid naming (about 10%) tasks beyond what had already been

    predicted by vocabulary and age.

    The results support the notion that poorer performance on phonological

    processing tasks is associated with lower receptive vocabularies and production of more

    atypical speech sound changes. Results are interpreted in the context of the accuracy of

    phonological representations. Thus, atypical sound changes are seen as reflecting poorly

    specified internal representations of the sound features of words.

  • Phonological Processing and Speech Production

    in Preschoolers with Speech Sound Disorders

    By

    Jonathan Preston

    B.S. Elmira College

    M.S. Syracuse University

    DISSERTATION

    Submitted in partial fulfillment of the requirements for the degree of

    Doctor of Philosophy in Speech-Language Pathology

    Department of Communication Sciences and Disorders

    Syracuse University

    August, 2008

    Approved: _______________________ Professor Mary Louise Edwards Date: ____________________

  • Copyright 2008 Jonathan Preston

    All rights reserved

  • ACKNOWLEDGEMENTS

    Thanks to the families that participated in this research, to the clinicians who

    referred children, and to my colleagues and friends in the field who offered

    encouragement and intellectual support. Thanks in particular to my advisor, Dr. Mary

    Louise Edwards, for her support. I am appreciative of comments and feedback from my

    committee members, Dr. Raymond Colton, Dr. Linda Milosky, Dr. Benita Blachman, and

    Dr. Annette Jenner-Matthews. I also would like to thank Renail Richards for assisting

    with reliability, and Dr. Lawrence Shriberg for providing the Power Point stimuli for the

    syllable repetition task. In addition, Dr. Beth Prieve’s flexibility was important in

    making this project happen.

    This research was supported in part by the 2007 American Speech-Language-

    Hearing Foundation grant in Early Child Language awarded to the author.

  • v

    TABLE OF CONTENTS

    CHAPTERS:

    I : INTRODUCTION......................................................................................................... 1

    II : METHODS ................................................................................................................ 37

    III : RESULTS ................................................................................................................. 70

    IV : DISCUSSION........................................................................................................... 87

    REFERENCES ............................................................................................................... 105

    FIGURES

    Figure 1: Theoretical framework for the study.................................................................. 5

    Figure 2: Flow chart of procedures with number of participants..................................... 47

    Figure 3: Examples of PA stimuli.................................................................................... 60

    Figure 4: Scatterplots of speech sound production error types and phonological

    awareness Principal Component ............................................................................... 77

    Figure 5: Observed PA Principal Component scores and PA scores predicted by the

    regression (age, vocabulary, atypical sound changes) for the 43 children with SSD80

  • vi

    TABLES

    Table 1: Summary of speech sound error types and their suspected reflection of

    underlying phonological representations .................................................................. 26

    Table 2: Inclusionary criteria for the study...................................................................... 45

    Table 3: Descriptive statistics for the 43 preschoolers who participated in Part II and

    were used in the final analysis .................................................................................. 46

    Table 4: Summary of speech sound (in)accuracy for 43 preschoolers with SSD............ 71

    Table 5: Pearson’s correlation coefficients (r) of speech sound error types.................... 72

    Table 6: Summary of the performance of 43 children on the phonological processing

    tasks........................................................................................................................... 73

    Table 7: Pearson correlation coefficients (r) for the phonological awareness tasks for 43

    children with speech sound disorders ....................................................................... 74

    Table 8: Principal Component Analysis summary derived from the four Phonological

    Awareness tasks ........................................................................................................ 75

    Table 9: Hierarchical regression used to predict PA Principal Component .................... 78

    Table 10: Regression using PCC as the speech production variable to predict PA......... 81

    Table 11: Regression explaining variance in Phonological Memory (Syllable Repetition

    Task) ......................................................................................................................... 83

    Table 12: Regression explaining variance in Rapid Naming (average Z scores of two

    Rapid Naming tasks) ................................................................................................ 85

  • vii

    APPENDICES

    Appendix A: Transcription Rules and Coding Sound Changes..................................... 125

    Appendix B: Errors with Interacting Sound Changes: Which is Preferred? ................ 146

    Appendix C: Words Used on the Picture Naming Task ................................................ 150

    Appendix D: Phonological Awareness Tasks................................................................ 151

    Appendix E: Syllable Repetition Task (from Shriberg et al, 2006)............................... 155

    Appendix F: Rapid Naming Task .................................................................................. 156

    Appendix G: Complete Correlation Matrix ................................................................... 157

    Appendix H: Measurement Issues ................................................................................. 159

    Appendix I: Regression Diagnostics.............................................................................. 163

    Appendix J: Caveats and Limitations: The Role of Children’s Experiences................ 166

    Appendix K: Speech Perception .................................................................................... 168

  • 1

    I : INTRODUCTION

    Literacy problems are a significant international concern, with as much as 15-

    20% of the world’s population having some sort of reading difficulty (International

    Dyslexia Association, 2000). Early identification of such problems is essential so that

    early intervention can take place. Fortunately, it is now possible to identify skills in

    preschool that are good predictors of later literacy. This study will focus o

View more